1. Field of the Invention
The present invention relates to an internal structure of a compact camera, and more particularly, to mounting positions of various electronic components on one mounting board within the compact camera.
2. Description of the Related Art
Conventional compact cameras are designed to include a variety of electronic components, mounted very closely within the camera. The camera size is reduced due to the high-density of components located within a small area. Typical elements in a camera include a photographic lens barrel, a film cartridge chamber, a film windup spool chamber, a viewfinder device, a photometric device, an autofocus device, motor drive devices, a display device, and strobes.
A plurality of mounting boards, such as flexible printed wiring boards, have been used to interconnect all of the electrical components within the camera body. For example, the LCD display device, providing a display of information to the exterior of the camera, and the motor drive device, using an IC for performing motor drive control, are not conventionally mounted on a single board. The LCD is presently mounted on the rear cover of the camera body, while the motor drive IC is presently mounted on the front surface of the spool chamber. Using many mounting boards, however, results in an inefficient use of space, a relatively "large" compact camera, and higher manufacturing costs.
In addition, certain components inside the compact camera operate with low power, and are therefore highly influenced by electrical noise. For example, autofocus devices (hereinafter "AF" devices) and autoexposure devices (hereinafter "AE" devices) are controlled by a very low current. The electrical noise, generated either inside or outside of the camera, adversely affects the accuracy of the low-power devices.
In order to reduce the effects of noise on the AF device, for example, a signal processing circuit (i.e., an IC) is mounted as close as possible to the AF receiving unit. If, however, the signal processing circuit cannot be mounted adjacent to the AF receiving unit, the circuit must be carefully shielded. In a relatively larger camera, there is generally no problem with mounting the circuit close to the AF receiving unit, or providing a shield around the circuit.
In compact cameras, however, it is difficult to maintain the same design as in larger cameras. For example, there is no space available to mount the circuit close to the AF receiving unit due to the smaller size of the camera body. Moreover, if the signal processing circuit were to be mounted at a distant place, there still is not enough space to provide the necessary shielding for the circuit. Because the length of the electrical connections between the AF receiving unit and circuit is relatively large in a compact camera, it is more susceptible to noise. Low-power devices in conventional miniaturized cameras do not, therefore, function accurately.
A camera typically includes operating switches, such as a switch to change over the Speedlight flash photography mode. In compact cameras, the switches are located in close proximity to the signal processing circuit of the AF device. The operating switches themselves generate electrical noise when operated. The operator also generates electrical noise which is received by the AF device. Noise from the switches and the operator cause the AF device to function erroneously.